a(n) is the number of perfect powers m^k with k>=3 (A076467) <= 10^n.

Terms

a(0) =1a(1) =2a(2) =7a(3) =17a(4) =38a(5) =75a(6) =152a(7) =306a(8) =616a(9) =1260a(10) =2598a(11) =5401a(12) =11307a(13) =23798a(14) =50316a(15) =106776a(16) =227236a(17) =484737a(18) =1036002a(19) =2217529a(20) =4752349a(21) =10194727a(22) =21887147a(23) =47020054a(24) =101065880a(25) =217325603a(26) =467484989a(27) =1005881993a(28) =2164843035a(29) =4660016778